Chemical liquid supply apparatus and a chemical liquid supply method

1. A chemical liquid supply apparatus comprising: a liquid tank accommodating chemical liquid; a closed buffer tank section having a ceiling wall and a bottom wall enclosing therebetween a liquid accumulation chamber, which is connected to said liquid tank through a liquid introduction flow path connected through said ceiling wall, a liquid discharge vent being connected to said liquid accumulation chamber through said bottom wall; a filter section having a filter inlet connected with said liquid discharge vent of said buffer tank section, and a filter outlet; a pump having a pump inlet connected to said filter outlet through a pump inlet-side flow path and a pump outlet connected to a liquid discharge flow path to which a discharge nozzle is connected, an expandable and contractible pump chamber being provided in said pump; a return flow path connected between said pump outlet and said buffer tank section for returning, to said liquid accumulation chamber, the chemical liquid discharged from said pump; and a valved exhaust flow path connected through said ceiling wall of said buffer tank section for exhausting air from said liquid accumulation chamber, wherein under conditions where said liquid introduction flow path, pump inlet-side flow path, and liquid discharge flow path are closed, and where said return flow path and said exhaust flow path are opened, gas contained in said liquid accumulation chamber is exhausted via said exhaust flow path by contracting said pump chamber and returning the chemical liquid to said liquid accumulation chamber through said return flow path.

2. The chemical liquid supply apparatus according to claim 1 , further comprising an exhaust flow path connected to said filter section for exhausting gas contained in said filter section.